According to a conventional liquid pressure-feed device disclosed in Japanese Patent Laid-Open Publication No. Hei 8 (1996)-114175, a working fluid inlet port, a working fluid discharge port, a liquid inlet port and a liquid discharge port are formed in a closed vessel, and a float, a change-over valve, a snap mechanism and a liquid discharge valve are provided within the closed vessel, the snap mechanism having a pivot shaft supported within the closed vessel, a float arm and a sub-arm both adapted to rotate about the pivot shaft, further having a first shaft supported by the float arm, a second shaft supported by the sub-arm, and a spring mounted between the first and second shafts, the liquid discharge valve having a third shaft supported by the float arm, a liquid discharge valve arm mounted to the third shaft, and a liquid discharge valve body mounted to the liquid discharge valve arm to establish and block communication between the interior of the closed vessel and the liquid discharge port, the float being connected to the float arm, and the change-over valve being connected to the sub-arm through a power transfer shaft, with the pivot shaft being provided between the second and third shafts.
Thus, in the above conventional liquid pressure-feed device, the pivot shaft is provided between the second and third shafts. It is not that the third shaft is provided between the pivot shaft and the second shaft. This is because if the third shaft is provided between the pivot shaft and the second shaft there will arise the problem that the sub-arm positioned between the pivot shaft and the second shaft obstructs the movement of the third shaft.